Problems with tram from WV set 10308 running on curved tracks

[CoNSpiracy]

I have motorized the tram from the winter village set 10308 by following the official instructions, and wanted to program it to run back and forth in my winter village display over a distance of approx 2 meters. To make it a bit more interesting I wanted the route to contain curved tracks. However, the tram seems to have big problems in the curves (often slows down due to the friction) and even sometimes gets stuck. You can hear the motor working overtime but the tram just doesn’t move smoothly in the curves unless the speed is set at a really high level. This makes it virtually impossible for me to program with code in the PoweredUp app based on time delays, and the only way to automate it on curved tracks seems to be by installing a colour sensor and accepting that the tram will struggle its way through the curves in what sounds and looks as a very painful manner. Since I want the train to stop when each end of the tracks is reached, pause and then start up slowly, increase speed a bit (but remain at a realistic speed for a city tram) and then slow down again and stop at the other end, it is not really an option to just set the speed so high that it doesn’t get stuck in the curves.

Has anyone of you come across this, too? Found a solution?

I have also tried testing it with TrixBrix R56 curved tracks instead of the official Lego R40 curved tracks, and there it runs a bit better, but still with some problems. Has anyone tested with custom R72 tracks or above?

I am surprised and disappointed that TLG would release a “train” product like that, which can’t even run properly on their own official train tracks.

Edited October 6, 2023 by CoNSpiracy

[JopieK]

It might be due to the weight and the newer wheels without spokes. LEGO did test them well:

But in your case they appear to have issues. You could/should contact LEGO about it I think.

@zephyr1934 you made a 'promise' in that Topic, so maybe you already have found a solution ?! ;)

[zephyr1934]

8 hours ago, JopieK said:

But in your case they appear to have issues. You could/should contact LEGO about it I think.

Yes, definitely something to contact Lego customer service about. The tram should be able to make the curves okay, and given the popularity of the set I'm sure there would have been a wide outcry if the cars are fundamentally flawed.

If the issue is that it works fine if it were going in a loop, but the time variability is too much to rely on for your automation, that might be beyond lego specifications and not something they would be able to help with.

Two thoughts in that regard, perhaps removing the traction bands from one side of the motor might make it take curves better (on a curve the wheels on one side will want to move faster than those on the other side). The other thought is that a color sensor is not a bad idea to add if you can find the room. They are very cheap for what they do, and you could even add a color block to "increase power" as you go into the curve.

 

8 hours ago, JopieK said:

@zephyr1934 you made a 'promise' in that Topic, so maybe you already have found a solution ?! ;)

I think I caught covid a week after typing that (but there were no tests and officially no covid in the US at that point) and then I got distracted by a few things (grin). I'm pretty sure that was referring to making bearing holders for technic axles. I have since made a working prototype, but have not gone further yet. If there's a lot of interest by someone who wants to beta test they can PM me.

[AllanSmith]

Can you shorten the wheelbase? I put a 9v bogie only under mine to run on the old 9v track. No problems with the full curves.

[CoNSpiracy]

20 hours ago, AllanSmith said:

Can you shorten the wheelbase? I put a 9v bogie only under mine to run on the old 9v track. No problems with the full curves.

That might help. I have just followed the official instructions for motorization that came with the set, where the train engine part itself is only mounted with one set of wheels. The tram is pretty long so I’m sure the designers of the set have thought that it looks better with more distance between the wheel sets, but I think you are right that the long distance between them is the cause of the problem - plus two sets of wheels mounted on the train engine itself should also create better transfer of power. I will test and revert.

[CoNSpiracy]

Update: I have modded the tram so that the train engine brick is now centered underneath the tram and both wheel sets are now directly connected to the train engine brick. Surely this helps, although there is still a difference in the speed when the tram runs on a straight track vs. in a curve (R40 original Lego). The thing is that I want the tram to run back and forth at a fairly low speed as I think that resembles the real life tram behaviour best. I guess that with a "normal" train running on Lego tracks, I would likely generally run it with a higher speed than the low speed I am looking for here - I assume that if I tested a "normal" Lego train on a curved track at very low speeds, it would probably also struggle a bit in the curves and could get stuck at the very lowest speed settings.